The invention concerns a solar timepiece and a clock mechanism for such a timepiece.
Within the meaning of the present invention, a solar timepiece is defined as a timepiece with electronic timekeeping which draws its driving energy not from a stationary network or a battery, but by means of an energy storage device from solar cells for the conversion of light energy into electric energy, the solar cells being illuminated at least partially.
With the "Citizen Quartz Cryston Solar Cell" in 1976, a wristwatch appeared on the market wherein the four quadrants of the dial face were occupied by solar cells set into the plane of the dial face within the minute wheel works. As, however, the overwhelming presence of the solar cells in the dial face affected the aesthetic appearance excessively and detrimentally, further development tended to dimension and arrange the solar cells in a manner such that they were displaced as far as possible from the particular design sensitive area of the dial face. Thus, in contemporary solar wrist watches the solar cells are optically integrated in the minute wheel works or hidden under the glass ring of the wrist watch case (with a connection to the environmental illumination by means of specifically designed light conduction devices); or they are entirely removed from the dial face area of the watch and built, for example, into a side wall of the case.
In large timepieces there is sufficient space available outside the minute wheel works to be able to arrange the solar cells without difficulty outside the dial face.
It is an object of the invention to provide a solar timepiece and a clock mechanism for a solar timepiece, preferably in the form of a desk or wall clock, characterized by a convenient mutual layout of the solar cells and the clock mechanism itself, with favorable manufacturing conditions and stylistically attractive design possibilities.